Not much out there. Some opinions are that it would be safe to fire with modern subsonic .22 LR. Some say .22 short. Others call BS, but have no other info. The bolt seems to be the weak point, so I assume it's the recoil impulse that causes the damage, not pressure? So, 2 questions. First, ideas on ammo what would be safe to shoot in the gun? I absolutely don't want to damage it. Second, if I could get a newer bolt from a 39 with and "HS" sn, would it then be safe to shoot high velocity ammo? Obviously I'll keep the old bolt as this seems to be a collector gun. Thanks for any help.